package com.jwb.util;

import java.security.MessageDigest;

/**
 * 密码加密
 * 
 * @author Administrator
 * 
 */
public class Md5Str
{
	
	// 默认是 32位
	public  static String str2MD5(String _str)
	{
		char hexDigits[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
				'a', 'b', 'c', 'd', 'e', 'f' };
		try
		{
			byte[] strTemp = _str.getBytes();
			MessageDigest mdTemp = MessageDigest.getInstance("MD5");
			mdTemp.update(strTemp);
			byte[] md = mdTemp.digest();
			int j = md.length;
			char str[] = new char[j * 2];
			int k = 0;
			for (int i = 0; i < j; i++)
			{
				byte byte0 = md[i];
				str[k++] = hexDigits[byte0 >>> 4 & 0xf];
				str[k++] = hexDigits[byte0 & 0xf];
			}
			return new String(str);
		}
		catch (Exception e)
		{
			return null;
		}
	}
	
	// 16位
	public  static String str2MD5to16byte(String _str)
	{
	
		return str2MD5(_str).substring(8, 24);
	}
	
	
	private static String byteArrayToHexString(byte b[])
	{
		StringBuffer resultSb = new StringBuffer();
		for (int i = 0; i < b.length; i++)
			resultSb.append(byteToHexString(b[i]));
		
		return resultSb.toString();
	}
	
	private static String byteToHexString(byte b)
	{
		int n = b;
		if (n < 0)
			n += 256;
		int d1 = n / 16;
		int d2 = n % 16;
		return hexDigits[d1] + hexDigits[d2];
	}
	
	public final static String str2MD5to32byte(String _str)
	{
		return Md5Str.MD5Encode(_str, "UTF-8");
	}
	
	public static String MD5Encode(String origin, String charsetname)
	{
		String resultString = null;
		try
		{
			resultString = new String(origin);
			MessageDigest md = MessageDigest.getInstance("MD5");
			if (charsetname == null || "".equals(charsetname))
				resultString = byteArrayToHexString(md.digest(resultString
						.getBytes()));
			else
				resultString = byteArrayToHexString(md.digest(resultString
						.getBytes(charsetname)));
		}
		catch (Exception exception)
		{
		}
		return resultString;
	}
	
	private static final String hexDigits[] = { "0", "1", "2", "3", "4", "5",
			"6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };
	
	public static void main(String args[])
	{
		System.out.println(str2MD5("111111"));
		System.out.println(str2MD5to16byte("111111"));
	}
}
